The burning rates of two types of propellants used in aircrew escape systems are being studied. It is known that the two types of propellants have different SD of burning rates. Two samples of n1 = 20 and n2 = 35 specimens are tested, and sample mean burning rates are c1 = 19.05 cm/s and 12 = 25.37 cm/s, sample SD's are $1 = 3.81 cm/s and $2 = 3.97 cm/s. Test the hypothesis that these two types of propellants have the same mean burning rate at level a = 0.05